Presenter:

Long Zou(School of Physics and Astronomy, Shanghai Jiao Tong University)

Authors:

Long Zou(School of Physics and Astronomy, Shanghai Jiao Tong University)

Wei Ku(Tsung-Dao Lee Institute)

Zhi Wang(School of Physics, Sun Yat-sen University)

We demonstrate that the main low-energy structures of the normal-state optical conductivity of the cuprates can be described naturally from the picture of tightly bound pre-formed pairs. Specifically, we show that the observed onset at ~100meV (and its long tail extending toward zero energy) originate from inter-band excitations near the van Hove singularities of the pre-formed pairs. Without using any free parameter, our results reproduce not only the correct energy of the onset, but also the non-monotonic trends of its temperature and doping dependence. Our study reveals the bosonic nature of the low-energy carriers and provides a strong support for the picture of tightly bound preformed pairs in describing the high-temperature superconductivity and other low-energy physics of the cuprates.